Who Invented the Diesel Engine?

Posted Tuesday, Mar 5, 2013 by Allen B. Ury

Today, the word “diesel” is so generic its letters are all lowercased. But it didn’t start out that way. It used to be “Diesel.” Capitalized. As in Rudolf Diesel, the brilliant German engineer who invented the technology that now bears his name.

So who was Rudolf Diesel, and how did he come to invent the engine that powers so much of today’s industry and transportation?

A German Born in France

Rudolf Christian Diesel was born in 1858, the son of Bavarian immigrants then living in Paris. When Diesel was 12, his parents sent him to live with his aunt and uncle in Ausburg so he could become fluent in the German language. There, Diesel developed an interest in engineering — his uncle taught mathematics — and entered the newly founded Industrial School of Ausburg. Just two years later, he received a merit scholarship from the Royal Bavarian Polytechnic of Munich.

While at Royal Bavarian Polytechnic, Diesel befriended one of his professors, Carl von Linde, a leading expert in the new field of gas separation and refrigeration technology. After suffering a near fatal bout of typhoid, Diesel graduated and moved back to Paris to join von Linde in designing and building a modern refrigeration and ice plant in the French capital. Diesel served as plant’s director for several years.

In 1890, Diesel — now married with children — moved to Berlin to continue his work for von Linde. But Diesel was restless. He wanted to go into business for himself. Legally prohibited from exploiting the refrigeration patents he had acquired while working for von Linde, he was forced to apply his talents to another field. He chose the explore ways to make steam and internal combustion engines more efficient.

A Near Death Experience

One of Diesel’s first experiments involved a steam engine powered by ammonia gas. During one test, the engine exploded, injuring him seriously. Diesel spent several months in the hospital. Even after his release, he suffered health and eyesight problems that would plague him for the rest of his life.

In early 1893, Diesel published a paper titled, “Theory and Construction of a Rational Heat-Engine to Replace the Steam Engine and Combustion Engines Known Today.” In it, he described an engine in which air is compressed to such a degree it gives off enough heat to ignite a combustible fuel. From a thermodynamic standpoint, this should release more of the fuel’s potential energy that would steam or spark-driven combustion engines. Later that same year, Diesel received funding from MAN, a German engineering company, to put his theories into practice.

The Diesel Engine Is Born

Diesel’s first compression-ignition engine delivered 26 percent efficiency. While low, it was still more than twice the 12-percent efficiency delivered by contemporary steam engines. By 1897, he had developed his first “practical” engine, which delivered an astounding 75-percent efficiency. Surprisingly, it wasn’t powered by petroleum, but by peanut oil. Diesel was an early champion of what we now call “biofuel,” believing farmers should be able to grow the fuels that power the engines of private agriculture.

He displayed this engine at the Paris Exhibition Fair of 1898. It was an instant hit.

Between 1898 and 1913, Diesel continued to develop and ultimately sell his revolutionary engine to buyers in the manufacturing and transportation industries. Because early Diesel engines were large and heavy, they were best used in stationary situations, such as factories, and in large ships, replacing less efficiency steam engines. They would later prove critical to the Germany’s development of submarines (U-boats).

A Mysterious Death

On September 29, 1913, Rudolf Diesel boarded the post office steamer Dresden in Antwerp, Belgium, on the first leg of a business trip to London. After dining, he returned to his cabin…and was never seen again. Ten days later, sailors aboard a Dutch fishing boat discovered a badly decomposed body floating in the North Sea off Norway. They removed some personal items from the corpse, including a wallet and eyeglass case, then returned it to the sea. Diesel’s son, Eugen, later identified these items as his father’s.

Was Diesel’s death a suicide? Rumor was he had long suffered depression. Was it murder? There’s speculation that Germany did not want Diesel’s technology sold to the English, as both countries were gearing up for what would soon become World War I. Or perhaps it was just an accident.

The cause of Diesel’s tragic death will probably never be known. But his legacy remains a matter of public record. Today, diesel engines power everything from massive cruise ships to automobiles, trucks to oil rigs. Their efficiency remains unmatched. And as petroleum prices rise and supplies dwindle, perhaps Diesel’s dream of biofuel engines will also become a reality.

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